content: /* ===========================================================
   * JFreeChart : a free chart library for the Java(tm) platform
   * ===========================================================
   *
   * (C) Copyright 2000-2012, by Object Refinery Limited and Contributors.
   *
   * Project Info:  http://www.jfree.org/jfreechart/index.html
   *
   * This library is free software; you can redistribute it and/or modify it
   * under the terms of the GNU Lesser General Public License as published by
   * the Free Software Foundation; either version 2.1 of the License, or
   * (at your option) any later version.
   *
   * This library is distributed in the hope that it will be useful, but
   * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
   * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
   * License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this library; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
   * USA.
   *
   * [Oracle and Java are registered trademarks of Oracle and/or its affiliates.
   * Other names may be trademarks of their respective owners.]
   *
   * -----------------------
   * TimeSeriesDataItem.java
   * -----------------------
   * (C) Copyright 2001-2012, by Object Refinery Limited.
   *
   * Original Author:  David Gilbert (for Object Refinery Limited);
   * Contributor(s):   -;
   *
   * Changes
   * -------
   * 11-Oct-2001 : Version 1 (DG);
   * 15-Nov-2001 : Updated Javadoc comments (DG);
   * 29-Nov-2001 : Added cloning (DG);
   * 24-Jun-2002 : Removed unnecessary import (DG);
   * 07-Oct-2002 : Fixed errors reported by Checkstyle (DG);
   * 13-Mar-2003 : Renamed TimeSeriesDataPair --> TimeSeriesDataItem, moved to
   *               com.jrefinery.data.time package, implemented Serializable (DG)
   * ------------- JFREECHART 1.0.x ---------------------------------------------
   * 09-Jun-2009 : Tidied up equals() (DG);
   * 17-Jun-2012 : Removed JCommon dependencies (DG);
   *
   */
  
  package org.jfree.data.time;
  
  import java.io.Serializable;
  
  import org.jfree.chart.util.ObjectUtilities;
  
  /**
   * Represents one data item in a time series.
   * <P>
   * The time period can be any of the following:
   * <ul>
   * <li>{@link Year}</li>
   * <li>{@link Quarter}</li>
   * <li>{@link Month}</li>
   * <li>{@link Week}</li>
   * <li>{@link Day}</li>
   * <li>{@link Hour}</li>
   * <li>{@link Minute}</li>
   * <li>{@link Second}</li>
   * <li>{@link Millisecond}</li>
   * <li>{@link FixedMillisecond}</li>
   * </ul>
   *
   * The time period is an immutable property of the data item.  Data items will
   * often be sorted within a list, and allowing the time period to be changed
   * could destroy the sort order.
   * <P>
   * Implements the <code>Comparable</code> interface so that standard Java
   * sorting can be used to keep the data items in order.
   *
   */
  public class TimeSeriesDataItem implements Cloneable, Comparable<TimeSeriesDataItem>, Serializable {
  
      /** For serialization. */
      private static final long serialVersionUID = -2235346966016401302L;
  
      /** The time period. */
      private RegularTimePeriod period;
  
      /** The value associated with the time period. */
      private Number value;
  
      /**
       * Constructs a new data item that associates a value with a time period.
       *
       * @param period  the time period (<code>null</code> not permitted).
       * @param value  the value (<code>null</code> permitted).
       */
      public TimeSeriesDataItem(RegularTimePeriod period, Number value) {
          if (period == null) {
              throw new IllegalArgumentException("Null 'period' argument.");
          }
          this.period = period;
          this.value = value;
      }
  
      /**
       * Constructs a new data item that associates a value with a time period.
       *
       * @param period  the time period (<code>null</code> not permitted).
       * @param value  the value associated with the time period.
       */
      public TimeSeriesDataItem(RegularTimePeriod period, double value) {
          this(period, new Double(value));
      }
  
      /**
       * Returns the time period.
       *
       * @return The time period (never <code>null</code>).
       */
      public RegularTimePeriod getPeriod() {
          return this.period;
      }
  
      /**
       * Returns the value.
       *
       * @return The value (<code>null</code> possible).
       *
       * @see #setValue(java.lang.Number)
       */
      public Number getValue() {
          return this.value;
      }
  
      /**
       * Sets the value for this data item.
       *
       * @param value  the value (<code>null</code> permitted).
       *
       * @see #getValue()
       */
      public void setValue(Number value) {
          this.value = value;
      }
  
      /**
       * Tests this object for equality with an arbitrary object.
       *
       * @param obj  the other object (<code>null</code> permitted).
       *
       * @return A boolean.
       */
      @Override
      public boolean equals(Object obj) {
          if (this == obj) {
              return true;
          }
          if (!(obj instanceof TimeSeriesDataItem)) {
              return false;
          }
          TimeSeriesDataItem that = (TimeSeriesDataItem) obj;
          if (!ObjectUtilities.equal(this.period, that.period)) {
              return false;
          }
          if (!ObjectUtilities.equal(this.value, that.value)) {
              return false;
          }
          return true;
      }
  
      /**
       * Returns a hash code.
       *
       * @return A hash code.
       */
      @Override
      public int hashCode() {
          int result;
          result = (this.period != null ? this.period.hashCode() : 0);
          result = 29 * result + (this.value != null ? this.value.hashCode() : 0);
          return result;
      }
  
      /**
       * Returns an integer indicating the order of this data pair object
       * relative to another object.
       * <P>
       * For the order we consider only the timing:
       * negative == before, zero == same, positive == after.
       *
       * @param o1  The object being compared to.
       *
       * @return An integer indicating the order of the data item object
       *         relative to another object.
       */
      @Override
      public int compareTo(TimeSeriesDataItem o1) {
          return getPeriod().compareTo(o1.getPeriod());
      }
  
      /**
       * Clones the data item.  Note: there is no need to clone the period or
       * value since they are immutable classes.
       *
       * @return A clone of the data item.
       */
      @Override
      public Object clone() {
          Object clone = null;
          try {
              clone = super.clone();
          }
          catch (CloneNotSupportedException e) { // won't get here...
              e.printStackTrace();
          }
          return clone;
      }
  
  }
  